Conduit connection for tanks



Nov. 30, 1948.

E. H. MEYERS ET AL CONDUIT CONNECTION FOR TANKS 2 Sheets$heet 1 Filed May 18, 1944 I Will/1% E M n E m Nfi T. 5 A 3 0E I L LA a Nov. so, 1948. E. H. MEYERS ET AL 55,

I CONDUIT CONNECTION FOR TANKS Filed May 18, 1944 2 Sheets-Sheet 2 IN V EN TORS ELLWOOD H.MEYERS 8 BY WALTER S.GAINES miwu m AT TOR NEYS Patented Nov. 30, 1948 'l'lED STATES PATENT OFFICE Gaines,

Chagrin Falls, Ohio,

assignors, by

mesne assignments, to'Republio Industries, Inc., New York, N. Y.', a corporation ofDelaware Application May 18, 1944, Serial No. 536,147

6 Claims. I

This application'is a -continuation-in-part of our co-pending application, Serial No. 390,630, filed April 26, 1941, now Patent No. 2,360,359.-

This invention relates to the art of making connection between a conduit, pipe, or the like and a tank, box, vat or other vessel.

In the various arts, when a conduit is threadedly connected to the wall of a vessel, thethickness of the wall is often less than the necessary axial extent of the threadsand a so-called spud of suitable thickness is provided, either integral with and a part of the vessel wall or attached to it, and having threads to-receive the conduit.

Also, vessels often contain material, for example, liquid, which is corrosive with respect to the vessel wall and spud, and the wall and spud are accordingly painted or' otherwise coated with a non-corrosive coat, the coat being continuous from the wall of the vessel outwardly over the spud wall'and out to the conduit-receiving spud threads. But it is generally impracticable to insure that the non-corrosive coat will extend uninterruptedly entirely to the threads, or that the threads themselves will be so tightly sealed as to prevent corrosive liquid from entering them. It follows that such coats fail of their main purpose of I preventing access of the corrosive liquid to bare metal, because bare metal is exposed to its action either on the threads themselves or on the spud surfaces adjacent the threads.

The-present invention has been made to solve this problem generally, and, in particular, to provide a solution applicable to the attachment of conduits to vessels, the walls of which arecoa-ted with vitreousenamel, typical of which are the enamelled hot water tanks used to supply hot water to a domes-tic or like water system.

It is desirable, in enamelled tank fabrication, to attach separately formed spuds to the tank wall, and it is known that this can most advantageously be done by electric resistance or electric flash welding, but the attachment ofspuds to tanks of the enamel-coated class, in a leakproof and pressure-proof manner, introduces problems the solution of which is not obvious and many attempts have been made to provide a satisfactory spud and means of attaching it to the tank wall in such cases.

Some struoturemeans or method must: be pro-- vided to insure that the enamel'coa-t, particularly on the inside of the tank, will form solidly and completely over the spud surfaces and tank wall surfaces adjacent thereto, and not leave bare metal exposed tothe corrosive action of the hot water or other contents of the tank; and

the threads of the spud must .be left free from enamel slip so that fused enamel will not form thereon;. and in this connection the spud must be attached to the tank wall in such manner'that the enamelling of the tank and the surfaces of the spud may be performed after the spudis attached; and the outside diameter of thespud and its zone of connection with the tank wall must. berelatively' large'because when a conduit has been connected to'it, the conduit is in the nature of a lever and even a slight side thrust thereon which may inadvertently be given to it by the plumber installing it, will, because of the leverage, bend thewall to which the'spud is attached' and crack the enamel coat, but at-the same time, the mass of metal in the spud at such large outside diameter must not interfere with the welding of it to the relatively thin wall of the tank; and at the juncture of the spud with the tank wall, all surfaces that are to be enamelled must either be planar or must be curved on sumciently great radii as to'cause the'enamel to form continuously and solidly, and such surfaces should preferably be inherent in the structure so as not to require reaming or grinding or rounding metal-working operations.

The invention-comprises in general, besides the spud proper or thick portion of the vessel wall having threads into which the threaded conduit is screwed, a non-corrosive insert formed of such material as to render it susceptible of being molded into intimate sealing engagement with the non-corrosive coat of the vessel or spud to seal off the non-corrosive coat on an unbroken area of the coat and inwardly of the spud threads; and which is also susceptible of having supplemental threads formed thereon after it is assembled with the threaded spud which supplemental threads are incontinuation with the spud threads and into which also the conduit is screwed and which seal off the conduit thread-s inwardly of the spud. threads. Thus no corrodible part of the vessel is exposed to corrosive contents of the vessel except the inner'end of the conduit itself and if desired it also can be made of corrosion- .proof' material.

It is amongthe objects of the invention:

To provide generally an improved conduit connection for tanks, and other vessels;

To provide generally an improved connection for-joining a conduit to a coated vessel in communication with its interior;

To provide a spud connection for vessels of the type comprising a threaded conduit receiving spud welded to the vessel wall and in which both the spud and the vessel wall may be coated completely and solidly with enamel;

To provide a conduit spud connector of relatively large diameter which may be welded to a vessel wall on a small welding area in an improved manner;

To provide in a conduit connection for enamelled vessels an improved construction whereby at the juncture of the spud and vessel Wall, surfaces of large radius may be provided in an improved manner to insure the formation thereon of a solid coat of enamel;

To provide a conduit connection for vessels having corrosion-proof coated walls, comprising an insert element for effecting in an improved manner the sealing-off of the inner coat of the vessel and the sealing off of the conduit threads;

To provide an improved method for making a welded juncture between a spud and a tank wall to facilitate the coating of spud and the tank wall.

' Other objects will be apparent to those skilled in the art to which our invention appertains.

' Our invention is fully disclosed in the following description taken in connection with the accompanying drawing in which:

Fig. l is a longitudinal sectional View to approximately full scale of a part of the wall of a vessel and a pair of dieelements in the positions which they assume preparatory to performing a metal working operation on the vessel wall at the point to which a spud connector is to be attached according to our invention;

Fig. 2 is a View similar to Fig. l but with the die parts in' a subsequent position and with the metal working operation partly performed;

' Figs. 3 and 4 are views of another pair of die' elements in successive positions which they occupy in completing the metal working operation initiated by the die elements of Figs. 1 and 2; Fig. 5 is a view illustrating the wall of the vessel upon which the metal working operation has been performed and illustrating a spud body embodying a part of our invention associated therewith in position to be welded thereto and illustrating the welding electrodes in broken line;

Fig. 6 is a view similar to Fig. 5 but illustrating the spud body after it has been welded onto the vessel wall and after both the tank body and the spud body have been coated with vitreous enamel; V

Fig. 7 is a view of the parts of Fig. 6 and illustrating an insert element constituting. part of the spud connector in. its preferred form and the method of applying the insert element;

Fig. 8 is a view similar to Fig. 7 illustrating threads which have been formed on the insert element continuous with threads on the spud body element and illustrating a conduit screwed into the spud threads; and I Figs. 9 to 13 are respectively alternative embodiments of my invention, each having in common, however, the basic features of the structure illustrated for example in Fig. 8.

While the present invention may be applied, to advantage, to vessels of various kinds, it will be described more particularly herein as applied to enamel coated tanks, to whichseparately formed spuds are attached; inasmuch as this is one of its more important uses. The invention has been illustrated with tank walls coated both inside and outside with enamel but as will become apparent hereinafter the outside enamel coat may be omitted if desired. The inside enamel coat of the tank is provided primarily for the purpose of preventing corrosion of the tank wall by the contents of the tank. Typical of such tanks are the hot water tanks used as reservoirs for hot water in domestic Water systems, and as is well-known the hot water has corrosive action on the walls of the tank for purposes of economy they are made from steel. Commerce demands a conventional form of tank comprising a cylindrical tubular body, and heads at the ends of the body, and spuds for conduit connections to the tank are provided at various points on the body wall and on the heads. The spud connection herein described may be applied either to the body wall or to the head walls and for simplicity of illustration herein we have chosen to illustrate it in connection with the body wall and in connection with a tank the walls of which are made of steel.

Referring to Fig. l of the drawing we have shown at I a fragment of the body wall of a tank and the body I is provided with a perforation 2A. A metal working operation is performed upon the metal of the body at the perforation as follows. A pair of dies 2 and 3 is provided, the lower die 3 having an annular concave rounded die surface 4, and on its upper portion having a pilot portion 5 of substantially the diameter of the perforation 2A. The upper die element 2 has an annular convex rounded portion 8 corresponding to the portion 4. The tank wall I is telescoped over the lower die 3 and the pilot 5 inserted in the perforation to position it, and then the two die elements 2 and 3 are moved forcibly together by a press or the like and they take upthe Positions illustrated in Fig. 2, bending and drawing the metal adjacent the perforation 2A into the form shown in Fig. 2, where, as will be seen, it takes the form of an outwardly projecting tubular portion I, joined to the body I by a connecting portion 8, the die-formed curvature of which is of relatively large radius compared with the thickness of the metal of the body I. The dies land 3 are then withdrawn from each other and the body of the tank removed therefrom and placed upon another lower die element 9, as shown in Fig. 3 disposed directly under an upper die element ID having a downwardly projecting die portion II, which has an annular concave rounded die portion I2, the die portion II substantially fittting the tubular formed portion I. The die elements I0 and 9 are then forced toward each other by a press or the like, and the portion I2 of the upper die continues the metal working operation of the body, leaving the metal as shown at I3 in the form of an outwardly projecting tube which, proceeding axially there along, outwardly from the body I, tapers first inwardly and then outwardly, the tapers as shown being continuous one into the other and being curved on a relatively large radius I4; the tube I3 thus being of smaller diameter in its intermediate portions than in portions farther outward axially.

This outwardly drawn tube I3 is reproduced in Fig. 5 wherein also is shown the body I5 of the spud. This spud body is generally in the form of a thick disc with a threaded opening I6 therethrough, the threads being taper or pipethreads to receive va threaded conduit as will appear later, and between the threads IBand the outer periphcry I! of the body. is formed a groove I8 which leaves an annular peripheral edge I9.

The annular edge I9 of the spud body I5 is welded to the outer edge 20 of the tube I3, the parts being positioned for this operation as shown in Fig. 5. Welding electrodes 2| and 22 are disposed. one upon the spud and the other upon the inner wallof the body l, and the parts are pressed together while electric current is passed there through and the weld thereby effected. After the Spud-body f and the tube 13 have been thus weldedtogether they appear as inFig. 6.

In this connection it may be stated that while the-body wall I, at the time of forming the tube tibis cylindrical, the die elements 2, 3, 9, and H1 form the tube l3 so that its upper edge is substantially in a plane whereby the peripheral edge l$,'-engaged therewith for welding the two to gether, may be planar.

Asmentioned hereinbefore, any number of such' spudbodies 15 may be, in a similar manner, welded to similar tubes It on the body wall or on the' heads of the body not shown; and after such spud bodies have been welded on as des" cribed the tank body, the heads and the spuds are coatedwith vitreous enamel, which may be err-the inner walls of the tank and spuds or upon botlr the inner and outer walls.

-Wl'i'en both the inner and outer walls have been enamelled, the spud preferably appears as in Fig. 6, wherein the inner coat is shown at 23 on the body t, extending outwardly-over the tube l3 as atl land over the wall of the groove l8 as at ii and out' toward the threads l6; and on the outer'wall of the body as at 26, extending over the tube f3 as at Hand over the outside of the spud body as at 28and toward the threads l6.

It is desirable to prevent enamel from forming on the threads, and to this end, when the Wet enamel slip is applied preparatory to forming theenamel coat, and has dried, it may be rescrewing in a plug before applying the wet slip and taking it out after the slip is applied.

After the enamel coats have thus been applied, an insert 29, Figs. 7 and 8, is added to the spud as an element thereof. For the present description this insert may be considered as of soit metah-Other suitable materials will be referred to later. The insert 29 is first molded into thespud structure as shown at Fig. 7 and subsequently is threaded as shown in Fig. 8 with a supplemental thread 30 continuous with the thread Hi-of the spud. This insert 29 is applied by pouring a quantity of molten metal into the tubular portion ltdescribed above, and to avoid the necessity of having to drill a hole therein upon which thewthreads 30 may be formed, a hole may be molded in the insert. One means for accomplishing this result is illustrated in Fig. '7. A molding plug 3 l of cylindrical form, provided with threads 32 fitting the threads I 6 of the spud body, and having a head 33, is screwed into the spud by-turning the head 33, so that the molten metal will flow around the plug 3|, and the plug 3! may have draft whereby it may be removed after the metal solidifies. At the time of applying the molten metal for the insert, the body and spud may be'turned upside down with respect to their position in Fig. 7, and the molten metal may be conducted through a conduit 34 which has been projected into the body through another spud opening on the body or on a head and with the end of the conduit adjacent the tube l3, to discharge the molten metal into the space around the plug 3|; or the molten metal may be injected through a bore 35 in the head 33 of the plug and axially through the plug and caused to flow over the end of the plug and into the space between theeplug and the tube [3.

Whenthe: insert 29 has solidified, and the plug 6 M nes-been withdrawn, within the spud structure by its-interlock with the convex configuration of the tube 43 upon which it is, as will be apparent, molded andis further interlockedby its being molded into the groove [8-, the interlock preventing its displace ployed, one such alloy-being tin and lead, 50% each; Other-alloys may be utilized and a metal" alloy which expands upon solidifying maybe employed if desired, such alloys being well-known in the art. The alloy in any case is preferably onewhich has no chemical reaction with the enamel coat in engagement with it.

The-spudconnection is now complete and a conduit such as that'show-n at 36- in Fig. 8 may be screwed-thereinto and will make leak' and pressure proof juncture with the insert 29, or with the insert and the body [5, on the threads thereof. The insert-besides performing'the function of making a pressure and liquid-tight seal at-its threads with the threads of the conduit 36,- performs another important sealing function. The

metal oi theinsert being molded and solidified on the enamel'at 24 and Has above referred to, makes intimate sealing contact therewith and prevents corrosive liquid orthe like, even if under pressure, from creepingover the enamel to the threads' lfi even if the enamel coat does not extend all the way to the threads. It will be understood that, as mentioned above, it is desirable that there-be no enamel on the threads of the spud body l5; and that the dried slip, before fusingih is removed therefrom; but it is imprac-- ti'cable to insure that the enamel coat will extend. entirely to the threads and stop there, so that without the insert 29, when the conduit 36 has been screwed into the body E5 of the spud, there would inevitably'be bare-metal exposed on the spud adjacent thethread I6 which would beattacked by the corrosive liquid; but by employing the insert; even if :there be bare metal at such point, theliquid cannot reach it, being sealed off therefrom bytheinsert. Ihe metal of the insert itself is not subject to corrosion by the liquid'inv the: tank if a suitable alloy be employed therefor, and as would be the case with the alloys men,- tioned above.

It follows that with the spud structure described above, after the conduit 36 has been screwedthereinto, no bare corrodible metal is exposed to the action of liquid in the tank except that'of the conduit 36 itself, if it be of corrodible material, and to render the entire system cor-.

rosion-proof, the conduit 36' may be of non-conv its initial position with the undesirable result of bending the metal at its juncture with the tank wall and consequently cracking the enamel coats thereon.

The insert 29 therefore effects both on. its radially outer and on its radially inner parts, a

' liquid and pressure-proof seal to prevent corthe insert is maintainedrbsive liquid from creeping outwardly either along the inner enamel coat or along the threads of the conduit.

In Fig. 9 we have illustrated a modification of our invention, which in some cases it may be preferable to employ, inasmuch as, with this form, the outwardly projecting tube I3 is not required.

Referring to this figure, in which again the conduit connection or spud structure is associated with the wall of the tank body, the spud body 31 having conduit receiving threads 38, is Welded as at 39 to the body I. The spud body 31 is generally of tubular form as illustrated, and on the inner wall thereof is rovided with a' groove 42 before it is welded on as described.

The body 31 is in alignment with a perforation 43 in the body, which perforation may be made before the spud body is welded on, or may be punched out of the body wall after the spud body is welded on, whichever method is preferred. The periphery of the perforation 43, preferably after the weld has been made, is rounded off as shown at 44, to insure that an enamel coat will form continuously and solidly thereon; and the body I and spud body 31 are coated with enamel, the inner enamel cost 45 continuing outwardly over the rounded edge 44 as at 46, upwardly along the inner wall of the spud as at 41, and over the wall of the groove 42 as at 48 and inwardly toward the threads 38, as at 49; and the outer enamel coat 50 extending upwardly over the spud body as at and inwardly toward the threads 38 as at 52. The enamel slip from which the enamel coat thus described is fused, is, as usual, first applied and dried, and the threads may be kept free from enamel as described above.

After the enamel coat has been formed, an insert 53 of soft metal is molded in the groove 42, and may be molded therein by any suitable means,

that preferred being the one more completely i described in connection with the, above firstdescribed form of the invention.

' The insert has threads 54 formed or out thereon by a tap or the like, continuous with the threads 38 on the spud body.

In the modification of Fig. 10, the tube I3 is first formed on the body I as described for the form of Figs. 1 to 8. A spud body 55 is provided, generally of tubular form, and having pipe threads 56 formed thereon, and on its outer periphery is provided with a depending skirt 5!. In this form, the spud is welded to the body proper, instead of to the edge of the tube I3. The parts are enamel-coated With an inner coat 6|. This inner coat covers all of the surfaces of the projection 62. The outer coat 68 covers the tank body I, and the outer Walls of the spud body toward the threads 56. A soft metal insert 51 is formed in the structure and threads 68 formed thereon continuous with the threads 56.

This insert 61 like the insert 53 of theform of Fig. 9 is molded into and interlocked with the structure so that it cannot become displaced, the aforesaid insert 53 being molded into the groove 42 formed in the spud body 31, and the insert 61 being interlocked by what in effect, is a groove 69 formed by the Wall of the spud body and the inner surface of the tube I 3, and these inserts perform the functions described for the corresponding insert 29 of Figs. 1 to 8 above described.

In Fig. 11 is shown a modification of the spud body shown in Fig. 10, this body I0 having an annular shoulder 'II formed on the outside of the spud body, and the upper electrode I2 instead of engaging the outer end. of the spud body as in the form of Fig. 10 engages the said shoulder I I, and this shoulder being adjacent the lower end of the skirt 51a, the lower end 58 of the skirt will be brought to welding temperature with a minimum of welding current. Otherwise the construction indicated by Fig. 11 will be welded,

enamelled and provided with a threaded insert,

in the same manner as in connection with the form of Fig. 10.

In the modification illustrated in Fig. 13, the body I of the tank is provided with a coniform inwardly extending portion around the opening. Afiixed to the outer face of the wallasvby welding in accordance with any of the modes previously explained and preferably centrally of the opening in the wall is a metallic annulus 9| provided with a flanged portion 92 with which the welded connection is made. At one or more points circumferentially spaced about the annular space 93 is a fillet 94 which may be provided conveniently by locally depositing small amounts of weld metal as for example from a fusible weldirrg electrode. The inner coating 95 extends about the coniform end 90 of the wall I and the,

molded insert 96 is in overlying relation to said coating. Continuous pipe threads such as 91 are formed on the molded insert and the outer end of the annulus 9|. The provision of the fillets 94 cooperating with the local area of enlarged diameter, in which the molded insert 96 is contained, securely lock the insert and the welded assembly against relative movement in both the axial and circumferential direction. It is within the contemplation of this invention to provide fillets such as 94 in any of the structures illustrated in any of the remaining figures. The radial inward extent of the fillet should be such as to leave a substantial amount of the molded insert material between the threads and the fillet.

From the foregoing it will be apparent that the insert is particularly advantageous when the Whatever the type and character of the coat,

it will be observed'that in the connection structure there is generally a pocket on the tubular spud body at the outer end of which is a thickened threaded portion (the threaded spud) to receive the conduit; and that there is a recess laterally of the thread axis, and that an annular insert is trapped in the pocket and interlocked therewith and sealed upon the coat; and has supplemental threads in it continuous with the firstnamed threads. As stated, this continuous thread is a taper thread, contemplating the screwing thereinto of a conduit having a taper thread out thereon in the usual manner, and if desired, the

taper thread on the insert may be of slightly smaller diameter than that of those convolutions of the thread which are on the spud proper, whereby when the conduit is screwed in it will be propelled inwardly by the threads on the spud proper and caused to tightly engage and seal upon the threads of the insert.

It will be apparent furthermore that the liquid sion, and that therefore the advantages of the sealing function may be enjoyed when it is aptrated in'Fig. 12. Here the wall'of the vessel, '13,

is integral with the thickened :portion .74. thereof having threads T into which the conduit 16 is screwed, as would be the case the vessel .wall were, for example, made of cast metal. A pocket TI is formed inwardly of the conduit threads 15, and has a recess 18 formed in the wall of the "pocket. The insert 19 is moldedtinto the pocket and recess and has supplementaljthreads afl.continuous with the threadslE. A separate attached spud is not employed here, and the walls are not coated, and the recess is not annular.

As to the material of the insert, while metal alloy is preferred as described above, other materials may be utilized which are susceptible to being pressed or expanded or molded into the structure and interlocked therewith suificiently to prevent displacement; and which are susceptible to having threads formed thereon. Such materials include synthetic resins, tars, waxes, packings, plastics, etc.; and in the case of some such materials the interlock referred to may be effected by cement between the insert and the adjacent wall surface instead of by a molding recess as described.

When a metal alloy is employed for the insert the threads may be cut thereon as described; or they may be cut thereon at the same time and by the same operation which cuts the threads 16 in the spud body l5; or they may be molded in the insert by pouring the molten metal around a threaded plug. In this connection, the plug 3| of Fig. 7 would be threaded instead of cylindrical, and the metal of the insert 29 would be molded with threads corresponding thereto in the nature of a die casting. And in the case of the other materials mentioned above, the threads can be molded or cut or otherwise formed, in situ or not, as Will occur to those skilled in the art in accordance with the insert material utilized, without the necessity of further illustration or description herein.

Obviously the conduit itself may be made from any desired material determined by the nature and intended uses of the tank, vat, box, trough or other vessel to which it is connected and by the character of the contents of the vessel.

While we prefer to carry the enamel coat over the tube l3 and over the spud skirt and body and on toward the threads, it will be apparent that the enamel coat need not in all cases be carried that far; it may terminate for example on the tube I3. Ihe essential feature is that the insert shall overlap the enamel coat to a substantial extent suflicient to effect a seal between the coat and the insert. The extent of the enamel coat in the structure may thus be varied to a degree without departing from the spirit of our invention.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

We, therefore, particularly point out and distinctly claim as our invention:

1. A conduit connection for a vessel wall, comprising an extension on the face of said well about an opening therein, such extension providing a passage with its axis extending at an angle to the planeof said wall; aninsertadherently molded and solidified in saidpassagaand a continuous pipe thread formed in part on saidextension and in part on said molded insert.

2. A conduit connection for a vessel wall, comprising an extension on the face of said wall about an opening therein, such extension providing a passage withits axis extending atv an angle to the plane of said wall, a corrosion resistant coating on the inner face of saidwall and extending outwardly, over the inner surface of said passage, an insert of corrosion resistant material adherently molded and solidified in said passage in overlying relation bonding and sealing with said corrosion-resistant'-coating, and a continuous pipe thread formed in-part on said extension and in part on said molded insert.

3. A conduit connection for a vessel wall, comprising an annular extension on the face of said wall about an opening therein, such extension providing a substantially cylindrical passage with its axis extending at an angle to the plane of said wall, a corrosion resistant coating on the inner face of said wall and extending outwardly over the inner surface of said passage, an annulus of corrosion resistant material adherently molded and solidified in said passage in overlying relation bonding and sealing with said corrosion resistant coating, and a continuous pipe thread formed in part on said extension and in part on said molded annulus.

4. A conduit connection for a vessel wall, comprising an annular extension on the outer face of said wall about an opening therein, such extension providing a substantially cylindrical passage with its axis extending at an angle to the plane of said wall, a corrosion resistant coating on the inner face of said wall and extending outwardly over the inner surface of said passage, an annulus of corrosion resistant material adherently molded and solidified in said enlarged local area in overlying relation bonding and sealing with said corrosion resistant coating, such molded annulus interlocked mechanically with the inner surface of said passage, and a continuous pipe thread formed in part on said extension and in part on said molded annulus.

5. A conduit connection for a vessel wall, comprising an annulus welded to the outer face of said wall about an opening therein, such Welded assembly providing a substantially cylindrical passage with its axis at substantially right angles to the plane of said wall, with an intermediate local area of such passage having an enlarged diameter, a corrosion resistant coating on the inner face of said wall and extending outwardly over the inner surface of said passage to the extent of at least a portion of said enlarged area, an annulus of corrosion resistant material adherently molded and solidified in said enlarged local area in overlying relation bonding and sealing with said corrosion resistant coating, and a pipe thread formed on the outer portion of said first named annulus and said molded annulus.

6. A conduit connection for a vessel Wall, comprising an annulus welded to the outer face of said wall about an opening therein, such welded assembly providing a substantially cylindrical passage with its axis at substantially right angles to the plane of said wall with an intermediate local area of such passage having an enlarged diameter, a corrosion resistant coating on the inner face of said wall and extending outwardly over the inner surface of said passage to the extent of at least a portion of said enlarged area,

an annulus of corrosion resistant material adherently molded and solidified in said enlarged local area in overlying relation bonding and sealing with said corrosion resistant coating, the inner surface of said passage so formed as to mechanically interlock with said molded insert securing the parts against both radial and axial relative movement, and a pipe thread formed on the outer portion of said first named annulus and said molded annulus.

ELLWOOD H. MEYERS.

WALTER S. GAINES.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Shelton Aug. 18, 1885 Fowle Mar. 26, 1901 Cromwell Jan. 6, 1931 Draper Apr. 25, 1939 Dodson Nov. 12, 1940 Dodson Aug. 26, 1941 Martin Dec. 16, 1941 Riegen- July 21, 1942 Wackman Aug. 29, 1944 Meyers Oct. 1'7, 1944 Koppel Oct. 31, 1944 Bodnar et a1 Nov. 21, 1944 

